This invention pertains to the art of coupling devices and more particularly to an improved sealing and gripping device.
The invention is particularly applicable to a tube coupling arrangement and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed for other uses in a variety of environments.
Fittings are commonly used to connect metal tubes and pipes to each other for use in a variety of applications, such as in the aerospace industry, to convey fuel, hydraulic control fluids, and the like in an aircraft or space vehicle. In these applications, it is critical that there be a secure connection between the coupling body and the tubes in order to withstand vibration and other adverse conditions without failure.
The fittings may be installed by a mechanical engagement or by threaded engagement. A mechanical engagement may include swaged and pressed fitted components which typically cannot be disassembled without destroying the fitting and/or tube. The threaded engagement of the fitting components enables their disassembly and reassembly to again form a fluid tight seal.
Of particular interest herein are more severe applications wherein seals for fluids and gases must be maintained under extreme conditions. For example, so-called high pressures applications at pressures in excess of 1000 psi and/or high temperatures. Even under these extreme conditions, it is necessary that acceptable seals be reproducibly formed and maintained. Less severe typical applications include automotive air-conditioning systems, oxygen systems in hospitals, instrumentation fittings for natural gas wells, and compressed hydrogen systems used in fuel cells or combustion engines.
The use of swaging to secure fittings to tubular members is known. The fittings and coupling elements may be secured to the tubular member by the direct application of radial forces to deform the tube inwardly and provide a swaged connection. U.S. Pat. No. 5,069,058 discloses a tool for providing such a swaged connection.
Axially swaged fittings including a sleeve surrounded by a deforming ring are also known. For example, U.S. Pat. No. 5,452,921 discloses such an arrangement. Related axially swaged fittings are shown in U.S. Pat. Nos. 6,517,126 and 3,375,026.